This invention relates to an antistatic layer for plastic film, particularly to a light-sensitive silver halide photographic material excellent in antistatic ability.
Generally speaking, plastic films have strong chargeability, which gives many restrictions in uses in many examples. For example, in light-sensitive silver halide photographic materials, supports such as polyethylene terephthalate have been generally used, which are liable to be charged particularly at lower temperatures during winter season. In recent days, when high sensitivity photographic emulsions are coated at high speed, or light-sensitive materials of high sensitivity are subjected to exposure treatment through an automatic printer, antistatic countermeasures are particularly important.
When a light-sensitive material is charged, static marks may appear by its discharging, or a foreign matter such as dust, etc. may be attached, whereby pinholes may be generated to deteriorate markedly quality and workability is lowered extremely for correction thereof. For this reason, antistatic agents have been generally used in light-sensitive materials, and recently, fluorine-containing surfactants, cationic surfactants, amphoteric surfactants, surfactants or polymeric compounds containing polyethylene oxide groups, polymers containing sulfonic acid or phosphoric acid groups in the molecule, etc. have been employed.
Particularly, chargeability control with a fluorine-containing surfactant or electroconductivity improvement with an electroconductive polymer has been frequently used and, for example, in Japanese Unexamined Patent Publications Nos. 91165/1974 and 121523/1974, an example of applying an ion type polymer having dissociable group in the polymer main chain is disclosed.
However, in these prior art, the antistatic ability will be deteriorated to a great extent by developing processing. This may be considered to be due to the fact that the antistatic ability is low via the steps such as the developing step using an alkali, the acidic fixing step, the step of washing with water, etc. Therefore, in the case when printing is conducted by further use of a treated film as in printing light-sensitive material, etc., the problems such as pinhole generation, etc. by attachment of dust, etc. will ensue. For this reason, for example, Japanese Unexamined Patent Publications Nos. 84658/1980 and 174542/1986 propose an antistatic layer comprising a water-soluble electroconductive polymer having carboxyl group, a hydrophobic polymer having carboxyl group and a polyfunctional aziridine. According to this method, antistatic ability can remain after the treatment, but transparency is still insufficient. For this reason, the transparency was improved by use of additives. Further, the antistatic layer had drawbacks that the adhesiveness between the antistatic layer and a hydrophilic colloid layer coated thereon is poor to cause peeling off of the films during photographic processing.